German submarine U-735 was a Type VIIC U-boat built for Nazi Germany's Kriegsmarine for service during World War II. Design German Type VIIC submarines were preceded by the shorter Type VIIB submarines. U-735 had a displacement of when at the surface and while submerged. She had a total length of , a pressure hull length of , a beam of , a height of , and a draught of . The submarine was powered by two Germaniawerft F46 four-stroke, six-cylinder supercharged diesel engines producing a total of for use while surfaced, two AEG GU 460/8–27 double-acting electric motors producing a total of for use while submerged. She had two shafts and two propellers. The boat was capable of operating at depths of up to . The submarine had a maximum surface speed of and a maximum submerged speed of . When submerged, the boat could operate for at ; when surfaced, she could travel at . U-735 was fitted with five torpedo tubes (four fitted at the bow and one at the stern), fourteen torpedoes, one SK C/35 naval gun, 220 rounds, and two twin C/30 anti-aircraft guns. The boat had a complement of between forty-four and sixty. Service history U-735 served as a training boat preparing U-boat crews for service in the Atlantic Ocean. Her home base was Horten Naval Base in Norway, from which she operated on short coastal patrols, practicing in fjords and channels for submarine warfare. A Type VIIC U-boat, U-735 was very useful for preparing sailors and officers for service in modern boats, as opposed to the new models usually used in training. Commissioned at Christmas 1942 in Danzig after an exceptionally long building period, U-735 was given to Oberleutnant zur See Hans-Joachim Börner, who remained in command of the boat right up to her destruction exactly two years later, when he was killed on board his ship. Dispatched to Norway, Börner soon became an expert on the Norwegian seaways, and was able to train a large number of sailors on his practice missions from Horten. On the 28 December 1944, RAF Bomber Command sought to eradicate the menace of submarines sailing from Norwegian bases, and launched a major raid on Horten with 57 Avo Lancaster bombers. U-735 was anchored in the naval harbour at Horten. When the air raid alarm came at 21.30, U-735 eventually succeeded in leaving the harbour, having had trouble starting